1. Field of the Invention
The present invention relates to a cell imaging device, a cell imaging method, and a sample cell for taking an image of a cell contained in a liquid sample.
2. Description of the Related Art
International Publication WO2008/007725 discloses an analyzer which takes images of particles included in urine in a preparation placed on a stage, and which analyzes the particles by using the obtained images. International Publication WO2008/007725 also indicates that: in order to avoid occurrence of focal displacement due to manufacturing errors of each preparation, a focusing mark is provided on one face of a glass slide of a coverslip; and focusing adjustment is performed such that the focal point is at the focusing mark. In International Publication WO2008/007725, the analyzer moves the stage by a predetermined distance in the vertical direction relative to the objective lens from the focusing position obtained through focusing adjustment using the focusing mark, and sets an analysis start position at which observation of particles is to be started. Next, the stage is moved in the vertical direction by a very small distance from the analysis start position. Then, when a focused state is detected, it is determined that a particle is present at the focusing position, and an image of the particle is taken at the focusing position. Subsequently, in order to take an image of a new particle in a different visual field region, the stage is moved in the horizontal direction and then stopped, the stage is moved up and down by a predetermined distance in the vertical direction relative to the focusing position of the immediately-preceding visual field region. Then, when a focused state is detected, an image of the particle is taken at this focusing position.
In the analyzer disclosed in International Publication WO2008/007725, the relative distance between the stage and the objective lens is changed in the vertical direction in each visual field region to detect a focusing position, and taking an image of a particle is performed at the detected focusing position. Thus, it takes a long time to take an image. In addition, every time the stage is moved to a new visual field region, the stage is moved in the horizontal direction and then stopped, and thus, particles in the preparation vibrate due to the stop of the stage. Therefore, in order to obtain a clear image of a particle, it is necessary to wait until such particle vibration stops. Thus, it could take a long time to take an image.